Spectral and multivariate analysis of electroencephalography (EEG) data has proved a useful tool in estimation of drug effects on brain activity and in the search for neuro correlates of behavioral states and performance. The proposed research will identify and characterize methadone interaction on both brain spontaneous electrical activity and behavioral performance in monkey and cat using these quantitative methods. Changes in the behavioral states may be rapid and transient with concomitant shifts in EEG records. Evoked potential analysis will be used in an attempt to distinguish the methadone overlay on normal brain function while the animal is performing under schedule-controlled conditioning paradigms. Dependence to methadone and withdrawal will be examined in the methadone self-administering monkey for alterations in sleep-awake cycles, behavioral performance and spontaneous EEG activity. Therefore, the investigation proposes careful definition of effects attributable to methadone as separate and sustaining trends apart from transient shifts in normal behavioral states not related to drug action. In addition, the antagonist naloxone and the classical narcotic agonist morphine will be an integral part of the investigation to compare conteractions and possible equivalencies respectively for these two drugs.